For years, David Fross stocked California native grasses at his nursery – with few takers.

"Why do you keep these weeds around?" chided a friend. "Who's going to buy them?"

Now, Fross has a hard time keeping his "weeds" in stock as California gardeners have discovered the water-saving ways of going native.

Fross is the founder of Native Sons Wholesale Nursery in Arroyo Grande, near San Luis Obispo. His business started when almost no one grew native plants commercially.

A combination of prolonged drought and environmental consciousness has made his nursery a hallmark in the California garden trade. Although closed to the public, Native Sons supplies native plants to more than 100 retail nurseries statewide, plus scores of other garden professionals.

Native Sons also is a partner in the University of California, Davis, Arboretum All-Star program, promoting 100 drought-tolerant plants.

"I'm growing 50 All-Stars in the nursery and 35 at my home," said Fross, who has specialized in natives for more than 30 years.

His devotion to California flora was nurtured early on at UC Davis by the arboretum's Warren Roberts. Last week, Fross returned as a guest lecturer to talk about plants and inspire more gardeners.

"What is a native garden? How do you define it?" Fross asked. "California has incredible diversity. In Death Valley, there's 2 inches of rain a year. Smith River near the Oregon border gets 80 to 100 inches of rain. Between those two extremes, there are more than 5,000 plants that grow native. How do you choose?"

First, look around, Fross suggested.

"Drive around your community," he said. "Look and see what's working. Talk to your local retailers and garden-center staffs. They've been answering questions for 25 years. They can tell you what that plant is on that corner you drove by.

"Garden design is a site- specific art form. You want local expertise. You also want to pay attention to your own garden – its sun and shade, its own microclimate. It's also really important to know where a plant came from originally and its needs, too."

Don't assume that all native plants are drought-tolerant, Fross said.

"A hundred inches is a lot of rain, and those plants up on the Oregon border are native, too."

Fross, who also teaches at Cal Poly, San Luis Obispo, has become a guru for native-plant lovers. In 2006, he published "California Native Plants for the Garden" with Carol Bornstein and Bart O'Brien (Cachuma Press, $27.95, 280 pages), a serious reference book cataloging the state's many possible crossovers from the wild to the backyard.

Fross also wrote "Ceanothus" (Timber Press, $39.95, 272 pages), devoted to California's iconic native lilacs. He's seen their popularity grow not only here but overseas, particularly in England, where gardeners sculpt the blue-flowered bushes into hedges or train them to cover walls.

In a gorgeous shade of blue, Ceonothus "Ray Hartman" ranks among the best for garden use. Fross suggested the large shrub as an ideal candidate for screens to block out ugly walls or other landscape eyesores.

As for those "weedy" grasses, Carex praegracilis – a native sedge – has become Native Sons' best-seller.

"We sell thousands and thousands of them each month for lawn replacements," Fross said.

And for good reason. This compact sedge stays green all summer, uses half the water of a traditional lawn and needs mowing only once a month.

Part of the challenge of growing native plants is that most California flora goes dormant in summer, not winter. It's an adaptation to our Mediterranean climate.

"Summer is when most people spend time outdoors and want to enjoy their gardens," he explained. "That creates a conflict. In all the years I've been designing gardens, I've only had one client say they wanted their garden to go dormant (in summer). … But there are ways to make native gardens look beautiful any time."

That includes mixing textures and colors, such as gray-green wormwoods (Artemisias) and striking blue-green succulent Dudleyas. When the silvery artemisias brown in summer, the dudleyas become striking focal points, "like blue stars amid blond strands," Fross said.

Even after decades of study, Fross said, natives still hold an incredible appeal.

"I look at a plant and it says to me, 'This is where I chose to be, and I'm going to be beautiful,' " he said. "And I want a piece of that in my garden."

Call The Bee's Debbie Arrington, (916) 321-1075.